Despite a campaign that's been running since 2006 to clean up Hong Kong's polluted skies through warmer air-conditioning, many businesses are continuing to freeze customers with temperatures much lower than the 25.5 degrees Celsius recommended by the Environmental Protection Department (EPD).

Their solution to the chill factor? Hand out shawls.

The Regal Riverside Hotel in Sha Tin, for example, drew complaints from Olympics guests over the chilly temperatures in its seafood restaurant.

'Eventually they just gave us shawls to stop us from shivering,' said one guest.

A spokesperson for the hotel said the air-conditioning was centrally controlled and could not be changed by restaurant staff. She suggested that chilled diners request to be seated 'farther away from the vents'.

The Action Blue Sky Campaign - with the slogan 'Clean Air for a Cool Hong Kong' - was launched by the EPD in July 2006, but more than two years on, its impact remains limited.

However, according to environmental affairs officer for Friends of the Earth, Angus Wong Chun-yin, Hong Kong is weaning itself off its air-conditioning addiction.

He said complaints about over-chilled buildings had tapered off from an average of five a month when the campaign was launched to only two over the past three months. 'I think people are gradually accepting that 25.5 degrees is an optimum indoor temperature,' he said.

But he admitted the group was aware some venues were still handing out shawls for shivering patrons.

'I know some restaurants and cinemas in Hong Kong provide shawls for customers,' he said, adding it was 'the culture in Hong Kong'.

Bill Hon, manager at the Beijing-Shanghai Restaurant in Taikoo Place, said his restaurant handed out shawls because the air-conditioning was centralised.

'We can't adjust it at one customer's request,' he said, adding the restaurant was warmer when it was full.

But Mr Wong of Friends of the Earth said strong air-conditioning was not the answer to Hong Kong's highly humid summers.

'People should improve ventilation and buy dehumidifiers, which are more efficient ways of using energy,' he said.

Air-conditioning accounts for between 30 and 40 per cent of Hong Kong's energy use, and increasing the temperature by just one degree can save energy by 3 per cent, he said, adding the 25.5 degree optimum was not widely understood.

Mr Wong said an actual setting of 25 degrees would on average result in a room temperature of 27 degrees.

'I understand it's hard to strike a balance . . . but I believe we can come up with something in between.'